The legislation assumes about $6 billion in leasing fees and bonus bids would be paid by energy companies to drill in the refuge. The federal government could keep half the money to fund various programs and the other half would go Alaska.

Opening ANWR is a key part of the Bush administration's national energy policy. The White House says tapping the refuge's potential 16 billion barrels of crude would boost domestic petroleum supplies and help reduce US reliance on foreign oil imports.

Democrats John Kerry of Massachusetts and Maria Cantwell of Washington will offer an amendment to strip the ANWR language from the budget bill. The lawmakers had hoped to offer their amendment on Wednesday afternoon, but delayed it until Thursday because of a backlog of other pending amendments. A vote on striking the ANWR language was expected later in the week.

Many Senate Democrats, and a handful of Republicans, oppose drilling in the refuge. They argue the amount of oil in ANWR is not enough to justify threatening the area's polar bears, caribou and other wildlife.

In an e-mail to his supporters on Wednesday, Kerry said the Bush administration was "so beholden to the big oil and gas companies that turning over America's most precious natural resources on a fool's errand search for the last drop of oil is all they can think about."

Democrats also doubt the government would be able to raise the $6 billion in fees, as called for in the budget bill, based on the much lower prices companies have paid in recent years to lease tracts in other areas of Alaska's North Slope.

"It is irresponsible to base the country's budget on highly speculative and dubious projections of lease revenues for the coastal plain of the Arctic National Wildlife Refuge," all nine Democrats on the Senate Budget Committee said in a letter last week to the panel's Republican chairman, Judd Gregg.

Twenty-four House Republicans also sent a letter to the House Budget Committee chairman, Republican Jim Nussle, urging him to keep Arctic refuge drilling out of the 2007 budget bill.

The administration has failed every year to convince Congress to give energy companies access to the ANWR.

Drilling supporters hope consumer anger over high gasoline prices and rising oil imports will encourage more lawmakers to vote for drilling in the refuge.

ANWR stretches across 19 million acres (7.7 million hectares) in the northeast corner of Alaska. The White House wants to offer 1.5 million acres (607,000 hectares) in the refuge's coastal plain for oil and natural gas exploration leases.

The Interior Department estimates the refuge could hold between 5.7 billion and 16 billion barrels of recoverable oil.